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PubMed2004

[Association of single nucleotide polymorphism of vitamin D receptor gene start codon and the susceptibility to prostate cancer in the Han nationality in Hubei area].

OBJECTIVE: To investigate single nucleotide polymorphism of vitamin D receptor (VDR) gene start codon in the Han nationality in Hubei area and its relationship to the susceptibility to prostate cancer (PCa), and to study the possible mechanism for PCa. METHODS: The VDR genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 80 patients with PCa and 96 normal male controls from the Han nationality in Hubei area, using endonuclease Fok I. Direct sequencing was done in part of the PCR products. RESULTS: The frequency distribution of Fok I alleles in this cohort all followed the Hardy-Weinberg equilibrium. The distribution of genotypes and alleles had no significant difference between PCa patients and normal male controls( P > 0.05). CONCLUSION: The results indicated no significant relationship between Fok I polymorphism of VDR gene start codon and PCa in the Han nationality in Hubei area.

Aged↗

PubMed1997

GTP hydrolysis controls stringent selection of the AUG start codon during translation initiation in Saccharomyces cerevisiae.

We have isolated and characterized two suppressor genes, SUI4 and SUI5, that can initiate translation in the absence of an AUG start codon at the HIS4 locus in Saccharomyces cerevisiae. Both suppressor genes are dominant in diploid cells and lethal in haploid cells. The SUI4 suppressor gene is identical to the GCD11 gene, which encodes the gamma subunit of the eIF-2 complex and contains a mutation in the G2 motif, one of the four signature motifs that characterizes this subunit to be a G-protein. The SUI5 suppressor gene is identical to the TIF5 gene that encodes eIF-5, a translation initiation factor known to stimulate the hydrolysis of GTP bound to eIF-2 as part of the 43S preinitiation complex. Purified mutant eIF-5 is more active in stimulating GTP hydrolysis in vitro than wild-type eIF-5, suggesting that an alteration of the hydrolysis rate of GTP bound to the 43S preinitiation complex during ribosomal scanning allows translation initiation at a non-AUG codon. Purified mutant eIF-2gamma complex is defective in ternary complex formation and this defect correlates with a higher rate of dissociation from charged initiator-tRNA in the absence of GTP hydrolysis. Biochemical characterization of SUI3 suppressor alleles that encode mutant forms of the beta subunit of eIF-2 revealed that these mutant eIF-2 complexes have a higher intrinsic rate of GTP hydrolysis, which is eIF-5 independent. All of these biochemical defects result in initiation at a UUG codon at the his4 gene in yeast. These studies in light of other analyses indicate that GTP hydrolysis that leads to dissociation of eIF-2 x GDP from the initiator-tRNA in the 43S preinitiation complex serves as a checkpoint for a 3-bp codon/anticodon interaction between the AUG start codon and the initiator-tRNA during the ribosomal scanning process.

Amino Acid Sequence↗

PubMed2006

A survey of mRNA sequences with a non-AUG start codon in RefSeq database.

Alternative initiation in translation is one of the important mechanisms in which multiple proteins are synthesized from a single mRNA. In many cases, translation initiation occurring at a non-AUG codon has been reported by several experimental studies. We have analyzed all mRNA sequences in the RefSeq database and found that coding regions of about 0.1% of the total mRNA sequences begin with a non-AUG codon (nonAUG mRNAs). Major fraction of non-AUG mRNAs is predicted from genomic sequences. More than 100 non-AUG sequences are highly curated and 52 of them are explicitly annotated that they use alternate start codons for translation initiation. Analysis of these sequences reveals that majority of the protein products contain domains that are DNA/RNA-binding, kinases, growth factors, or involved in immune response or cell proliferation. Thus, the proteins translated from non-canonical codons seem to be implicated in regulatory role and/or signaling mechanism. The sequence context of the non-AUG start codons shows that purine at -3 position and/or G at +4 position are strongly conserved and the corresponding genes give rise to alternate transcripts and/or multiple isoforms. We have also developed a database "nonAUG" (http://bioinfo.iitk.ac.in) that contains a collection of all mRNA sequences whose coding regions start with a non-AUG codon. nonAUG database will be continuously updated and is freely available to the scientific community.

Codon, Initiator↗

PubMed2026

Altered neuronal start codon stringency favors cap-independent repeat-associated non-AUG translation.

Intronic GGGGCC repeat expansions in C9orf72 cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). This expansion supports a non-canonical form of translational initiation known as repeat-associated non-AUG (RAN) translation to produce toxic dipeptide repeat proteins that contribute to neurodegeneration. Here, we find that the efficiency of RAN translation and its dependency on the 5' 7-methylguanosine mRNA cap are variable across cell types, with both rodent neurons and human iNeurons favoring cap-independent RAN translation from two distinct repeats (CGG and GGGGCC) across multiple reading frames. Treatment with an eIF4E inhibitor that blocks cap-dependent translation enhances RAN translation specifically in neurons. Intriguingly, cap-independent RAN translation exhibits less reliance on near-cognate codons for initiation than cap-dependent RAN translation. This finding led us to identify a surprising global alteration in neuronal start codon stringency as a contributor to the relatively higher cap-independent RAN translation in this cell type. This effect correlates with cytoplasmic redistribution of eIF1 in neurons and is reversed with overexpression of the eukaryotic initiation factor eIF5, which relaxes start codon stringency and preferentially enhances cap-dependent RAN translation. Together, these findings reveal several neuron-specific features of translational regulation that favor cap-independent RAN translation with implications for nucleotide repeat expansion disorder pathogenesis.

Neurons↗

PubMed2004

Nucleotides downstream of start codons show marked non-randomness in Escherichia coli but not in Bacillus subtilis.

This study aimed at measuring the nucleotide non-randomness in the region downstream of start codons in bacterial genes and to see if the non-randomness differs between biased and unbiased genes, in terms of the effective number of codons (Nc) and the codon adaptation index (CAI). In Escherichia coli, there was a marked elevation in nucleotide conservation for the genes having low Nc-values compared to the genes having high Nc-values, i.e the more biased genes showed a higher level of non-randomness. Likewise, the genes displaying high CAI-values showed stronger nucleotide conservation than the genes of low CAI-values. This elevated conservation is visible up to approximately 15-17 nucleotides downstream of the start codon, after which there is little difference. This indicates that there may be distinct selectional mechanisms acting upon the first 5-6 codons within genes in E. coli. In B. subtilis, these effects are less pronounced, if present at all. Furthermore, analyses of codons used in this region were not in support of the hypothesis that the elevation in nucleotide non-randomness is a question of selection for certain optimal codons.

Bacillus subtilis↗

PubMed1992

Importance of mRNA folding and start codon accessibility in the expression of genes in a ribosomal protein operon of Escherichia coli.

The trmD operon of Escherichia coli consists of the genes for the ribosomal protein (r-protein) S16, a 21 kilodalton protein (21K) of unknown function, the tRNA(m1G37)methyltransferase (TrmD), and r-protein L19, in that order. The synthesis of the 21K and TrmD proteins is 12 and 40-fold lower, respectively, than that of the two r-proteins, although the corresponding parts of the mRNA are equally abundant. This translational control of expression of at least the 21K protein gene (21K), is mediated by a negative control element located between codons 18 and 50 of 21K. Here, we present evidence for a model in which mRNA sequences up to around 100 nucleotides downstream from the start codon of 21K fold back and base-pair to the 21K translation initiation region, thereby decreasing the translation initiation frequency. Mutations in the internal negative control element of 21K that would prevent the formation of the proposed mRNA secondary structure over both the Shine-Dalgarno (SD) sequence and the start codon increased expression up to about 20-fold, whereas mutations that would disrupt the base-pairing with the SD-sequence had only relatively small effects on expression. In addition, the expression increased 12-fold when the stop codon of the preceding gene, rpsP, was moved next to the SD-sequence of 21K allowing the ribosomes to unfold the postulated mRNA secondary structure. The expression increased up to 150-fold when that stop codon change was combined with the internal negative control element base-substitutions that derepressed translation about 20-fold. The negative control element of 21K does not seem to be responsible for the low expression of the trmD gene located downstream. However, a similar negative control element native to trmD can explain at least partly the low expression of trmD. Possibly, the two mRNA secondary structures function to decouple translation of 21K and trmD from that of the respective upstream cistron in order to achieve their independent regulation.

Base Sequence↗

PubMed2005

Dual-domain, dual-targeting organellar protein presequences in Arabidopsis can use non-AUG start codons.

The processes accompanying endosymbiosis have led to a complex network of interorganellar protein traffic that originates from nuclear genes encoding mitochondrial and plastid proteins. A significant proportion of nucleus-encoded organellar proteins are dual targeted, and the process by which a protein acquires the capacity for both mitochondrial and plastid targeting may involve intergenic DNA exchange coupled with the incorporation of sequences residing upstream of the gene. We evaluated targeting and sequence alignment features of two organellar DNA polymerase genes from Arabidopsis thaliana. Within one of these two loci, protein targeting appeared to be plastidic when the 5' untranslated leader region (UTR) was deleted and translation could only initiate at the annotated ATG start codon but dual targeted when the 5' UTR was included. Introduction of stop codons at various sites within the putative UTR demonstrated that this region is translated and influences protein targeting capacity. However, no ATG start codon was found within this upstream, translated region, suggesting that translation initiates at a non-ATG start. We identified a CTG codon that likely accounts for much of this initiation. Investigation of the 5' region of other nucleus-encoded organellar genes suggests that several genes may incorporate upstream sequences to influence targeting capacity. We postulate that a combination of intergenic recombination and some relaxation of constraints on translation initiation has acted in the evolution of protein targeting specificity for those proteins capable of functioning in both plastids and mitochondria.

5' Untranslated Regions↗

PubMed1995

AUC is used as a start codon in Escherichia coli.

Overexpression of the polymerase II transcription factor E subunit alpha mRNA (TFIIE alpha) in Escherichia coli with the pET3a expression vector [Studier et al., Methods Enzymol. 185 (1990) 60-89] results in the production of a 50-kDa N-truncated polypeptide in addition to the 57-kDa wild-type polypeptide. Microsequencing analysis of the 50-kDa truncated protein and verification of the TFIIE alpha mRNA, showed that a Shine-Dalgarno-like sequence present 200 nucleotides downstream from the normal start codon could direct the use of an internal AUC codon. This codon should thus be added to the list of the non-AUG start codons.

Amino Acid Sequence↗

PubMed2001

A probabilistic method for identifying start codons in bacterial genomes.

As the pace of genome sequencing has accelerated, the need for highly accurate gene prediction systems has grown. Computational systems for identifying genes in prokaryotic genomes have sensitivities of 98-99% or higher (Delcher et al., Nucleic Acids Res., 27, 4636-4641, 1999). These accuracy figures are calculated by comparing the locations of verified stop codons to the predictions. Determining the accuracy of start codon prediction is more problematic, however, due to the relatively small number of start sites that have been confirmed by independent, non-computational methods. Nonetheless, the accuracy of gene finders at predicting the exact gene boundaries at both the 5' and 3' ends of genes is of critical importance for microbial genome annotation, especially in light of the important signaling information that is sometimes found on the 5' end of a protein coding region. In this paper we propose a probabilistic method to improve the accuracy of gene identification systems at finding precise translation start sites. The new system, RBSfinder, is tested on a validated set of genes from Escherichia coli, for which it improves the accuracy of start site locations predicted by computational gene finding systems from the range 67-77% to 90% correct.

Algorithms↗

PubMed1998

The vitamin D receptor gene start codon polymorphism: a functional analysis of FokI variants.

The vitamin D receptor (VDR) gene contains a start codon polymorphism (SCP) which is three codons upstream of a second start site (ATG). The SCP genotype can be determined with the restriction enzyme FokI, where "f" indicates the presence of the restriction site and the first ATG, while "F" indicates its absence. Recent evidence suggests that the ff genotype is correlated with lower bone mineral density (BMD) in some populations. The SCP results in alternate VDRs that differ structurally, with the F variant (F-VDR) being three amino acids shorter than the f variant (f-VDR). To determine whether there are functional differences between the f-VDR and the F-VDR, we studied the two VDR forms expressed in COS-7 cells. The proteins were distinguishable from one another on Western blots by their different mobilities, confirming the larger size of f-VDR. Ligand binding studies showed no significant differences between the affinities of the two VDR forms for [3H]-1,25-dihydroxyvitamin D3 ([3H]-1,25(OH)2D3) (Kd = 131+/-78 pM, f-VDR; Kd = 237+/-190 pM, F-VDR; p = 0.24); however, a 2-fold difference in affinity can not be discriminated by this method. There were no differences in the abilities of the two receptor forms to bind DNA as determined by electrophoretic mobility shift assays. The ability of the two VDR forms to transactivate target genes was investigated using three different vitamin D responsive luciferase reporter constructs: 24-hydroxylase, osteocalcin, and osteopontin. In these transactivation experiments, 1,25(OH)2D3 dose-response (0.1-10 nM) curves revealed that the ED50 values for transactivation were indistinguishable between the two VDR forms. Additionally, cultured human fibroblasts with FF, Ff, and ff genotypes had similar sensitivity to 1,25(OH)2D3 with respect to the induction of 24-hydroxylase mRNA. In summary, we were unable to detect significant differences in ligand affinity, DNA binding, or transactivation activity between f-VDR and F-VDR forms. We must emphasize, however, that the sensitivity of the methods used limits our ability to detect minor differences in VDR affinity and function. In conclusion, we cannot define a mechanism whereby the SCP in the VDR might contribute to population differences in BMD.

Analysis of Variance↗

PubMed1998

Vitamin D receptor gene start codon polymorphisms (FokI) and bone mineral density: interaction with age, dietary calcium, and 3'-end region polymorphisms.

Osteoporosis is a polygenic disease, whose determining loci have not yet been identified. Vitamin D receptor (VDR) gene polymorphisms in the 3'-end region (as determined by the enzymes BsmI and ApaI) have been inconsistently associated with bone mineral mass. More recently, VDR start codon polymorphisms (as determined by the enzyme FokI) have been found to be related to adult bone mineral density (BMD) in pre- and postmenopausal American women. We investigated the association between BMD and FokI genotypes in premenopausal European-Caucasian women as well as in prepubertal girls from the same genetic background and examined the interaction with VDR 3'-end region polymorphisms and with dietary calcium intake. Areal BMD (g/cm2) was measured by dual-energy X-ray absorptiometry at the level of the lumbar spine, femoral neck, and femoral shaft in 177 healthy premenopausal women (age range, 18.7-56.0 years) as well as in 155 prepubertal girls (age range, 6.6-11.4 years). Genotyping for FokI, BsmI, and ApaI VDR polymorphisms was performed using polymerase chain reaction methods. FokI genotype-dietary calcium interaction was cross-sectionally analyzed in all subjects and longitudinally in 103 prepubertal girls enrolled in a calcium intervention trial. The prevalence of FokI VDR gene polymorphisms in this cohort was 15% for ff, 50% for Ff, and 35% for FF. In the whole cohort of premenopausal women or prepubertal girls, no significant association was found between FokI VDR gene polymorphisms and BMD, even adjusted for age (Z score), weight, height, and calcium intake. Further analysis of FokI VDR gene polymorphisms and dietary calcium intake suggested a possible interaction in BMD determination, since a trend for an association with FokI genotypes was more evident at high than low calcium intake in both cross-sectional and longitudinal studies. Furthermore, cross-genotyping FokI and either BsmI or ApaI VDR polymorphisms suggested that the ff genotype was associated with a significantly lower lumbar spine BMD in bb and aa prepubertal girls. FokI VDR gene polymorphisms were not significantly associated with BMD in healthy European-Caucasian females. However, cross-genotyping of the VDR 3'-end and start codon polymorphic regions may provide a further insight into the complex determination of BMD.

Absorptiometry, Photon↗

PubMed2004

Interactions of eukaryotic translation initiation factor 3 (eIF3) subunit NIP1/c with eIF1 and eIF5 promote preinitiation complex assembly and regulate start codon selection.

The N-terminal domain (NTD) of NIP1/eIF3c interacts directly with eIF1 and eIF5 and indirectly through eIF5 with the eIF2-GTP-Met-tRNA(i)(Met) ternary complex (TC) to form the multifactor complex (MFC). We investigated the physiological importance of these interactions by mutating 16 segments spanning the NIP1-NTD. Mutations in multiple segments reduced the binding of eIF1 or eIF5 to the NIP1-NTD. Mutating a C-terminal segment of the NIP1-NTD increased utilization of UUG start codons (Sui(-) phenotype) and was lethal in cells expressing eIF5-G31R that is hyperactive in stimulating GTP hydrolysis by the TC at AUG codons. Both effects of this NIP1 mutation were suppressed by eIF1 overexpression, as was the Sui(-) phenotype conferred by eIF5-G31R. Mutations in two N-terminal segments of the NIP1-NTD suppressed the Sui(-) phenotypes produced by the eIF1-D83G and eIF5-G31R mutations. From these and other findings, we propose that the NIP1-NTD coordinates an interaction between eIF1 and eIF5 that inhibits GTP hydrolysis at non-AUG codons. Two NIP1-NTD mutations were found to derepress GCN4 translation in a manner suppressed by overexpressing the TC, indicating that MFC formation stimulates TC recruitment to 40S ribosomes. Thus, the NIP1-NTD is required for efficient assembly of preinitiation complexes and also regulates the selection of AUG start codons in vivo.

Alanine↗

PubMed1999

The cis acting sequences responsible for the differential decay of the unstable MFA2 and stable PGK1 transcripts in yeast include the context of the translational start codon.

A general pathway of mRNA turnover has been described for yeast in which the 3' poly(A) tail is first deadenylated to an oligo(A) length, leading to decapping and subsequent 5'-3' exonucleolytic decay. The unstable MFA2 mRNA and the stable PGK1 mRNAs both decay through this pathway, albeit at different rates of deadenylation and decapping. To determine the regions of the mRNAs that are responsible for these differences, we examined the decay of chimeric mRNAs derived from the 5' untranslated, coding, and 3' untranslated regions of these two mRNAs. These experiments have led to the identification of the features of these mRNAs that lead to their different stabilities. The MFA2 mRNA is unstable solely because its 3' UTR promotes the rates of deadenylation and decapping; all other features of this mRNA are neutral with respect to mRNA decay rates. The PGK1 mRNA is stable because the sequence context of the PGK1 translation start codon and the coding region function together to stabilize the transcript, whereas the PGK13' UTR is neutral with respect to decay. Importantly, changes in the PGK1 start codon context that destabilized the transcript also reduced its translational efficiency. This observation suggests that the nature of the translation initiation complex modulates the rates of mRNA decapping and decay.

3' Untranslated Regions↗

PubMed2002

A novel long distance base-pairing interaction in human immunodeficiency virus type 1 RNA occludes the Gag start codon.

The 5'-untranslated region (5'-UTR) is the most conserved part of the HIV-1 RNA genome, and it contains regulatory motifs that mediate various steps in the viral life cycle. Previous work showed that the 5'-terminal 290 nucleotides of HIV-1 RNA adopt two mutually exclusive secondary structures, long distance interaction (LDI) and branched multiple hairpin (BMH). BMH has multiple hairpins, including the dimer initiation signal (DIS) hairpin that mediates RNA dimerization. LDI contains a long distance base-pairing interaction that occludes the DIS region. Consequently, the two conformations differ in their ability to form RNA dimers. In this study, we have presented evidence that the full-length 5'-UTR also adopts the LDI and BMH conformations. The downstream 290-352 region, including the Gag start codon, folds differently in the context of the LDI and BMH structures. These nucleotides form an extended hairpin structure in the LDI conformation, but the same sequences create a novel long distance interaction with upstream U5 sequences in the BMH conformation. The presence of this U5-AUG duplex was confirmed by computer-assisted RNA structure prediction, biochemical analyses, and a phylogenetic survey of different virus isolates. The U5-AUG duplex may influence translation of the Gag protein because it occludes the start codon of the Gag open reading frame.

5' Untranslated Regions↗

PubMed1997

The vitamin D receptor start codon polymorphism (FokI) and bone mineral density in premenopausal American black and white women.

This study examines the association between bone mineral density (BMD) and a start codon polymorphism (SCP) at the translation initiation site of the vitamin D receptor (VDR) gene. The thymine/cytosine (T/C) polymorphism in the first of two start (ATG) codons can be detected by a restriction fragment length polymorphism (RFLP) using the endonuclease FokI, which recognizes ATG as part of its restriction site. F indicates absence of the first ATG and a VDR that is shorter by three amino acids. The FokI genotype was determined in 154 premenopausal American women (72 black and 82 white) who were 20-40 years old. BMD of the total body, femoral neck, and lumbar spine were measured by dual-energy X-ray absorptiometry. The distribution of the SCP genotypes differed significantly by race (p < 0.001): 4% of blacks versus 18% of whites were ff homozygous and 65% of blacks versus 37% of whites were FF homozygous. There was no statistically significant interaction between race and SCP genotype in analyses of BMD at any skeletal site. In the group as a whole, the ff women had femoral neck BMD that was 7.4% lower than that of the FF women. The ff white women had total body BMD values that were 4.3% lower and femoral neck values that were 12.1% lower than FF white women. Total body and femoral neck BMD did not differ significantly by genotype in black women, and spine BMD did not differ by genotype in either race. Addition of the SCP genotype to analysis of covariance models comparing BMD of the black and white women reduced estimated differences in femoral neck BMD between the two groups by about 35%. In conclusion, the SCP polymorphism, detected with the endonuclease FokI, appears to influence peak bone density, particularly at the femoral neck. Racial differences in its distribution may explain some of the racial difference in femoral neck BMD.

Adult↗

PubMed2025

Male proband with intractable seizures and a de novo start-codon-disrupting variant in GLUL.

Bi-allelic variants in GLUL, encoding glutamine synthetase and responsible for the conversion of glutamate to glutamine, are associated with a severe recessive disease due to glutamine deficiency. A dominant disease mechanism was recently reported in nine females, all with a de novo single-nucleotide variant within the start codon or the 5' UTR of GLUL that truncates 17 amino acids of the protein product, including its critical N-terminal degron sequence. This truncation results in a disorder of abnormal glutamine synthetase stability and manifests as a phenotype of severe developmental and epileptic encephalopathy. Here, we report the first male with a pathogenic de novo variant in the same critical region of GLUL, with a phenotype of refractory focal and generalized seizures, as well as developmental delays. We provide a detailed description of the disease course and treatment response.

Humans↗

PubMed2006

Multiple start codons and phosphorylation result in discrete Rad52 protein species.

The sequence of the Saccharomyces cerevisiae RAD52 gene contains five potential translation start sites and protein-blot analysis typically detects multiple Rad52 species with different electrophoretic mobilities. Here we define the gene products encoded by RAD52. We show that the multiple Rad52 protein species are due to promiscuous choice of start codons as well as post-translational modification. Specifically, Rad52 is phosphorylated both in a cell cycle-independent and in a cell cycle-dependent manner. Furthermore, phosphorylation is dependent on the presence of the Rad52 C terminus, but not dependent on its interaction with Rad51. We also show that the Rad52 protein can be translated from the last three start sites and expression from any one of them is sufficient for spontaneous recombination and the repair of gamma-ray-induced double-strand breaks.

Alleles↗

PubMed2003

[Association of polymorphisms of vitamin D receptor gene start codon and 3'-end region with bone mineral density in postmenopausal women].

OBJECTIVE: To determine whether vitamin D receptor(VDR) gene start codon polymorphisms and 3'-end region polymorphisms exerted a combined influence on bone mineral density(BMD) in Han postmenopausal women in Beijing area. METHODS: The VDR Fok I and 3'-end region genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism in 110 unrelated postmenopausal women. BMD was measured at the lumbar spine (L(2-4)), femoral neck(Neck), Ward's triangle(Ward's) and trochanter (Troch) using duel-energy X-ray absorptiometry. RESULTS: The frequencies distribution of Fok I, Apa I, Bsm I and Taq I alleles in this cohort all followed the Hardy-Weinberg equilibrium. No significant association of Fok I, Apa I or Taq I genotype with BMD in postmenopausal women was found when these polymorphisms were considered independently, except for Bsm I genotype. When a combined analysis of VDR gene Fok I and 3'-end region polymorphisms was carried out, cross-genotyping Fok I and Apa I polymorphisms was significantly associated with BMD at the L(2-4) (P<0.001), and cross-genotype of Fok I and Taq I was also significantly associated with BMD at the Neck and Troch sites (P<0.05). However, cross-genotyping Fok I and Bsm I polymorphisms was not significantly associated with BMD. Cross-genotyping Apa I and Bsm I or Taq I polymorphisms was not associated with BMD in postmenopausal women, either. CONCLUSION: Although Fok I polymorphisms of VDR gene were not significantly associated with BMD in postmenopausal women, VDR gene Fok I and 3'-region polymorphisms (Apa I and Taq I) had a combined effect on the BMD in postmenopausal women.

3' Flanking Region↗